Curve Object Deformed by Curve - Distortions (Artefacts)
switch to Edit mode, rotate text 90° in Z axis, so the text alongs Local Y axis (don't ask me why)





all control points set to Handle type (V) > Free





switch to Object mode and rotate along X axis 90°
add Curve Modifier > Deformed by Circle, Deformation Axis > -Z






Essential parts of successful deformation and avoiding other issues are


keep origins of both objects at the same place
align text direction to local Y axis
set handles type to Free


If a surface or shape isn't smooth enough increase Resolution U (Properties Editor > Object Data Properties > Resolution U). But first try increase deformation Curve, than Curve Object.